That alleged slight may have occurred when Jean either pressed or pointed his hand at Mendez's face, the source said.

"It wasn't over something bigger," said the source. "They had an argument. And the defendant says he was disrespected."

Mendez knew to look for the victim on Harrison Avenue, near Port Richmond Avenue, and shot the older man as he sat in his car about 2:40 a.m., the source said. The bullet hit Jean, a Port Richmond resident, in the eye.

Jean, who went by the nicknames "DJ" and "Tef," was an aspiring rap artist, and worked as a sales representative at the AT&T store on Richmond Avenue in New Springville.

Authorities said David Peart, 21, of Mariners Harbor, accompanied Mendez, and provided Mendez with the .45 caliber handgun used to slay Jean.